Baier earned bachelor's and master's degrees at the University of Otago in her native Dunedin, New Zealand.

In 1952 she went to Somerville College, Oxford, where she earned her PhD and met fellow philosophers Philippa Foot and G.E.M.

She was former President of the Eastern Division of the American Philosophical Association, an office reserved for the elite of her profession.

Baier received an honorary Doctor of Literature from the University of Otago in 1999.

Baier's approach to ethics is that women and men make their decisions about right and wrong based on different value systems: men take their moral decisions according to an idea of justice, while women are motivated by a sense of trust or caring.